According to the Bloomberg report, prosecutors allege JPMorgan withheld information from Italian regulators about a 1 billion euro ($1.36 billion) financing the New York-based bank arranged for Monte Paschi's takeover of Antonveneta in 2008.

Prosecutors also are seeking indictments against former Monte Paschi managers for obstructing regulators, market manipulation and falsifying filings, Bloomberg reported, citing people familiar with the matter.